Earth sciences

Acquisition and allocation of resources: genetic (co)variances, selection, and life histories

Article Abstract:

A resource acquisition and allocation model was used to determine the effects on life history of the acquisition of a single resource and allocation to two traits. Depending on whether priority allocation is given to fecundity or viability, different evolutionarily stable strategies in life history components arise. Primary allocation to fecundity gives allocation fractions of zero and one as its stable state, while primary allocation to viability has allocation fractions that depend on population growth rate, resource availability and population age-structure.

Physiology, allocation, and growth rate: a reexamination of the Tilman model

Article Abstract:

Tilman's model regarding the maximal relative growth rate that can be reached by plants in a resource-rich environment features both allocational and physiological components. These include the maximal relative growth rate, root and stem biomass, maximal rate of photosynthesis per unit of leaf biomass and the respiration rate per unit of total biomass. Tests reveal that the model accurately recreates the dilemma faced by vascular plant species in its efforts to optimize growth rate.

Mutualism and competition between plants and decomposers: implications for nutrient allocation in ecosystems

Article Abstract:

The interactions between plants and decomposers (microorganisms) are competitive and mutually symbiotic. Testable predictions about nutrient allocation in ecosystems are made assuming that microorganisms retain a fraction of mineralized nutrients to maximize their population biomass, and leave the rest for plant uptake. The available data on ecosystems reveal a predictable pattern among nitrogen flow rates and nitrogen fractions in plants, decomposers and non-living organic matter.